Thunkable is a spin off of the MIT App Inventor project. If you can program in App Inventor, you can program in Thunkable. Their goal is to get the App Inventor concept running on both Android and iOS (iPhone).
Visit Thunkable at http://thunkable.com
Thunkable, built on top of the open-source project MIT App Inventor, is a visual programming tool
There are indications that MIT App Inventor will focus on education and training applications and that spin offs will offer more powerful (and likely complex) features such as increased database functionality or media handling. These new features, oriented perhaps towards businesses and organizations (rather than education) might become a subscription service – but with added value in terms of features and capabilities.